This research will compare two delivery formats for effective individually-tailored behavioral self-regulation counseling - clinic-based vs. cell phone delivered - to improve treatment retention and adherence in people living with HIV in resource limited small cities and rural areas. Engagement, retention, and adherence to care are necessary to achieve HIV suppression and the long-term clinical management of HIV infection. Unfortunately, substance use, poverty, and other barriers impede the clinical care and compromise the health of many people living with HIV infection. Only about half of people with known HIV infection in the United States are retained in care and only one in five achieve successful viral control, a pattern that is known as the HIV treatment cascade. We will conduct comparative effectiveness research (CER) on two models of clinical intervention delivery using either (a) clinic office visit counseling or (b) cell phone-delivered counseling. Behavioral self-regulation counseling is an evidence-based individualized patient care approach to monitoring adherence, providing support, and offering guided corrective feedback to improve medication adherence and retention in care. This proactive intervention is designed to increase engagement in care, facilitate retention, maximize adherence and improve health outcomes. Behavioral self-regulation counseling has been demonstrated effective in both clinic-based and phone-delivered formats. However, the comparative costs and effectiveness of these alternative formats for delivering behavioral interventions in clinical care have not been tested. Our aim is to conduct comparative effectiveness research on behavioral self-regulation counseling to guide health policy and clinical resource decision-making. Participants are 200 men and 200 women living in high-HIV prevalence remote communities who actively use alcohol or other drugs and are receiving HIV treatment. Following screening, informed consent, and baseline assessments, participants will be allocated to receive either (a) behavioral self-regulation counseling integrated into their office-based care or (b) behavioral self-regulation counseling delivered at home by cell phone. Participants will be followed for 12-months following implementation. The primary endpoints are mapped onto the HIV treatment cascade and include a biomarker for alcohol use, clinic-confirmed retention to care, medication adherence assessed by unannounced pill counts, and HIV RNA (viral load). The study includes implementation research that will determine facilitators and barriers to clinic and cell phone implementation and cost accounting of resources expended to achieve optimal outcomes. A team of internationally recognized experts will form a working group to guide the operational evaluation at minimal added cost. This study will inform evidence- based care retention and adherence interventions for people living with HIV who are using alcohol or other drugs in resource limited settings.